PM urges vigilance in NSW amid hot temps

Prime Minister Julia Gillard is urging people in NSW to be vigilant as the state prepares for possibly the worst bushfire conditions in many years.

The mercury is expected to skyrocket in many parts of the state as a heatwave pushes super hot air from inland Australia into NSW.

In the far west the temperature in some towns is predicted to hit 45 degrees, while in Sydney a forecast 43 degrees will make it the third hottest day on record.

"We know that NSW is about to move into an extreme heat period," Ms Gillard told reporters in Hobart on Monday after being briefed by emergency service personnel on bushfires that have destroyed 100 homes in southern Tasmania.

"That does mean that there will be fire warnings in parts of NSW, that fire risk is extreme."

In parts of NSW, fire risk levels may move to "catastrophic", the prime minister warned.

"This is the time to be vigilant and I do particularly want to pass that message to the people of NSW as the temperature gauge starts to rise."